Apparatus for connecting gas-conducting conduit elements and method for connecting gas-conducting conduit elements - Patents.com

Abstract

The present invention relates to a device 100 for connecting a gas conducting conduit element 1, in particular a hydrogen conducting conduit element, to a counterpart 2, in particular a component, comprising at least one threaded body 10 configured for tight, in particular gas-tight engagement with the counterpart 2, a first seal 3 in the form of a valve body 3a or in the form of a flat seal configured for contact, in particular gas-tight contact, with a valve seat 4 provided on the counterpart 2, and a second seal 5 operating on the principle of sealing effect, in that the sealing effect is exerted or developed regardless of axial displacement, in particular in the installation direction E, which is necessary to create the sealing effect of the first seal 3.

Description

[Technical Field]

[0001] The present invention relates to a device for connecting a gas-conducting conduit element, in particular a hydrogen-conducting conduit element, to a counterpart, in particular a component, and also to a method for connecting a gas-conducting conduit element, in particular a hydrogen-conducting conduit element, to a counterpart, in particular a component. [Background technology]

[0002] Devices for connecting gas-conducting conduit elements, in particular fluid conduits for compressed hydrogen, to components into which gas is to be introduced, such as on-tank valves (OTVs), gas handling units (GHUs), gas pressure tanks or other gas-conducting components, or even components formed as connecting elements for different conduit elements, are known from the prior art. Since sealing plays a crucial role in the case of gases, sealing elements are usually used. This is particularly true in the case of high-pressure applications, such as conduit elements for compressed natural gas or compressed hydrogen. When sealing hydrogen in particular, suitable sealing elements with high diffusion resistance to hydrogen are crucial.

[0003] For example, Patent Document 1 describes a pipe connection including a connector having a conical bore and a nut having a conical surface, the connection being integrally formed on the pipe. The connection has a compression-generated gripping surface that is oriented in the same direction as the corresponding conical bore and conical surface. During the manufacturing of the connection, the pipe is deformed along a specific compression path to ensure that the connection does not set during installation or repeated installations, and as a result, does not begin to leak.

[0004] Ferrule-type connections or adapters are also well known and typically include a threaded connection nut, a threaded connection, and one or more ferrules mounted inside the connection nut. The connection nut typically has a contact surface (first contact surface) that engages or can be brought into engagement with a contact surface on the ferrule. For example, a cylindrical conduit, such as a pipe end, is inserted into the connection, and the ferrule tightly or closely surrounds the outer wall of the conduit end. When the connection nut is installed on the threaded end of the connection, an axial force is applied to the ferrule, which engages the contact surfaces of each of the ferrules and the connection in a compressive manner, resulting in radial displacement of portions of the ferrule, which tightly hold the outer wall of the conduit end. In many applications, the adapter can be assembled using a simple tool, such as a wrench.

[0005] In order to enable such threaded connections to be used in the aviation field, where there are strict requirements, for example, in terms of resilience, including temperature and load changes, as well as in terms of impermeability, so-called putties are frequently used in the prior art, which, when applied to the threaded connection, require a certain hardening time before further work can be carried out thereon. Furthermore, if a leak occurs in this threaded connection, it will be necessary to remove the threaded connection and carry out time-consuming repair work, and also to give the putty time to re-harden. For example, their use on aircraft wing boxes is time-consuming due to the limited available space, narrow access, and the large number of threaded connections.

[0006] Furthermore, such threaded connections are difficult to document, which is extremely important, especially in the field of explosion protection (ATEX), in vehicle manufacturing, and in this case, especially in aircraft construction. Therefore, methods and devices have been proposed in the prior art for evaluating the properties of parts of such mechanically applied connections. Properties that can be evaluated include, among others, the position of the conduit retention device on the conduit, the amount of axial compression or displacement of the conduit retention device, and the amount of clamping force applied to the conduit retention device when the conduit retention device is axially compressed or displaced.

[0007] Such methods are extremely time consuming and can only be performed by trained staff. However, even when strict safety precautions are in place, such methods are highly dependent on the individual tester and material and assembly errors can still result in inaccurate test results.

[0008] Alternating stresses (temperature and tension changes) can cause leaks, especially in the field of automotive engineering, and in this case especially in the field of aircraft construction. Due to the large number of threaded connections and the drawbacks of conventional threaded connections mentioned above, this can lead to considerable maintenance and assembly work.

[0009] A further drawback of conventional connection techniques for gas-conducting conduit elements is the fact that both the sealing element and the threaded element used to create the sealing effect are in direct contact with the medium to be sealed, particularly gas. While this is not as dramatic in the case of conventional gases such as natural gas, it can become a significant safety issue in the case of compounds used for hydrogen fluid conduits. Many materials, especially metals, are susceptible to so-called "hydrogen embrittlement" when in contact with hydrogen, which, especially when combined with alternating stresses (temperature and tension changes) and vibration, can often lead to leaks in the case of known connection techniques. Because hydrogen is the lightest of all chemical elements, achieving a permanently sealed connection point is difficult. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] DE 19511063 A1 Summary of the Invention [Problem to be solved by the invention]

[0011] In view of the above-mentioned problems when connecting gas conducting conduit elements, in particular hydrogen conducting conduit elements, the object of the present invention is, firstly, to create a defined sealing situation that can be recorded and proven, and secondly, to provide an apparatus and a method for connecting a gas conducting conduit element to a counterpart that is able to take into account the above-mentioned problems, such as hydrogen embrittlement and the occurrence of leaks caused by temperature and tension changes and vibrations, while at the same time facilitating a simplification of the design and therefore a reduction in assembly and maintenance work. [Means for solving the problem]

[0012] The aforementioned object is achieved by a device for connecting a gas-conducting conduit element, in particular a hydrogen-conducting conduit element, to a counterpart, in particular a component, as set forth in claim 1, and by a method for connecting a gas-conducting conduit element, in particular a hydrogen-conducting conduit element, to a counterpart, in particular a component, as set forth in claim 16.

[0013] In this respect, one of the basic ideas of the present invention is to provide a device for connecting gas-conducting conduit elements, preferably intended to conduct hydrogen, which device comprises two seals arranged one after the other or in series in the outflow direction of leaking or permeating gas and operating on two different sealing effect principles. In this respect, the first of the two seals, which is preferably the first in the outflow direction, i.e., arranged before the second of the two seals, is preferably formed as a seal that seals by pressing force. However, the second seal operates on the principle of sealing effect, in that its sealing effect is exerted or developed regardless of the axial displacement, in particular in the installation direction E, which is necessary to create the sealing effect (pressing force) of the first seal.

[0014] In this way, a sealing device for connecting a gas-conducting conduit element to a counterpart can be provided that has, on the one hand, a seal, i.e., a first seal, which can be recorded and verified by predetermined parameters that can be easily measured and recorded. The provision of a second seal further improves the sealing effect, in particular, in the unfortunate event that the first seal leaks, i.e., gas escapes through the first seal, the second seal continues to hermetically seal the connection point, thus buying time to repair the first seal before the gas actually escapes through the connection point to the outside. This is extremely advantageous, especially in the field of explosion protection.

[0015] According to one aspect of the present invention, a device for connecting a gas conducting conduit element, in particular a hydrogen conducting conduit element, to a counterpart, in particular a component, comprises at least one threaded body configured for tight, in particular gas-tight engagement with the counterpart, a first seal in the form of a valve body or in the form of a flat seal configured for contact, in particular gas-tight contact, with a valve seat provided on the counterpart, and a second seal operating on the principle of sealing effect, in that the sealing effect is exerted or developed regardless of axial displacement, in particular in the installation direction, which is necessary to create the sealing effect of the first seal.

[0016] The present device relates to so-called "mechanically applied connections," such as connector pieces, mating pieces, couplings, assembly pieces, valve inlets and outlets, valve connections, and the like, used in fluid systems or circuits, such as hydrogen supply systems in vehicles, that have fluid flow and fluid pressure. Such mechanically applied connections can be used with, but are not limited to, conduit connection pieces for pipes, tubing, or any other type of conduit, to connect a conduit end to any other conduit end, or to different parts, elements, or components of a fluid system, such as a valve housing. Such mechanically applied connections are characterized by a fluid-tight (gas-tight) seal and by mechanical strength to hold the connection together, including to hold the conduits together sufficiently even under vibration, stress, and pressure.

[0017] In this respect, it may be advantageous for the first seal to be formed as a so-called metal seal or curved seal, and / or for the second seal to be formed as a radial seal, elastic seal, O-ring, delta ring, liquid seal, etc., and / or for the second seal 5 to be arranged after the first seal in the outflow direction of the gas emerging from the gas conducting conduit element and leaking or permeating through the first seal.

[0018] A metal seal is understood to mean that two elements made of metal are pressed together under the influence of a force to create a fluid-tight connection between them. In such cases, an annular contact surface is usually created between the two elements, through which the medium or gas to be sealed can flow.

[0019] Furthermore, it is advantageous if the valve body has at least partially a conical, round, spherical or spherical shape and / or if the valve seat provided thereon has a tapered shape, in particular a conical shape.

[0020] It is also preferred that the first seal is formed on an end face of the threaded body, in particular on the end face of the threaded body descending into a recess in a counterpart (in the assembled or hermetically connected state) formed complementarily to the threaded body, and / or that the second seal is provided or formed on the circumferential surface of the threaded body, preferably cylindrical, facing the inner wall of a recess formed in the counterpart, preferably in the installed state.

[0021] According to a further embodiment, the valve body and the valve seat are configured such that an annular contact surface is formed, the central axes of the valve seat and the valve body are arranged parallel to each other, in particular coaxially, and the valve body is displaceable parallel to the two central axes, in particular in the installation direction.

[0022] The device also preferably has at least one fluid channel having an open end, the open end being disposed between the first seal and the second seal and configured to detect gas exiting the gas conducting conduit element and leaking or permeating through the first seal.

[0023] In this regard, "detect" should be understood as allowing the fluid channel to receive and flow through the leaking gas, so that the leaking gas can be directed to a downstream gas sensor, which can detect the leaking gas and signal the presence of a leak.

[0024] It is also preferred that at least one fluid channel be formed in the threaded body and / or the counterpart. If the fluid channel is formed in the threaded body, an autonomous unit with leak detection means can be formed, which results in an increased cost for the individual device (connection device), but this may nevertheless be advantageous in some applications. On the other hand, if the fluid channel or sniffer channel is integrated into the counterpart, particularly a component such as a gas handling unit (GHU), multiple sealing or connection points can be led to the sensor chamber, so that multiple sealing points can be monitored by a single sensor.

[0025] It would also be advantageous if the device, particularly the threaded body, were configured to perform a purely translational movement, particularly in the installation direction, during the creation of the gas-tight connection between the threaded body and the counterpart. In other words, the device is configured so that no rotational movement of the threaded body relative to the counterpart occurs or is necessary during the connection of the gas-conducting conduit element to the counterpart, particularly during the gas-tight connection using two seals arranged in series. This facilitates installation, particularly in the case of long conduit elements and conduit elements with multiple bends. This constitutes a significant advantage over known threaded connections, which are often screwed into the counterpart via an external thread.

[0026] In this respect, the threaded body can advantageously be provided with at least two, preferably four, through-holes for receiving the fixing screws, the through-holes being preferably provided on the flange projections of the threaded body and the through-holes being preferably arranged behind the two seals in the outflow direction of the gas emerging from the gas conducting conduit element and leaking through the first seal.

[0027] Further, the device may include a third seal, which may be formed as a radial seal, a resilient seal, an O-ring, a delta ring, an elastomeric sealing member, a liquid seal, or the like, and which is positioned after the first seal or after the second seal in the outflow direction of gas exiting the gas conducting conduit element and leaking through the first seal.

[0028] According to a further embodiment of the invention, the device further includes a second fluid channel having an open end, the open end being disposed between the second seal and the third seal and configured to detect gas leaking out of the gas conducting conduit element and through the first seal and through the second seal.

[0029] It is also advantageous if the gas conducting conduit element is gas-tightly connected to the threaded body by a welded connection, in this way a further possible leak point can be avoided, i.e. the connection point between the conduit element and the threaded body, and once the welding has been carried out a leak test can be carried out which can also be recorded.

[0030] It is also advantageous if, in the sealed state, the valve body of the first seal is pressed against a valve seat formed in the counterpart via a threaded connection, in particular via at least two, preferably four, clamping screws.

[0031] In this way, with a given tightening torque of the clamping screw, a relatively accurate pressing of the valve body against the valve seat can be achieved, so that the sealing contact of the corresponding elements can be guaranteed over a wide temperature range, and a device or screw connection can be achieved which can be recorded and therefore certified using the applied tightening torque.

[0032] According to a further embodiment of the invention, the valve body, in particular the screw body, and / or the valve seat are made of metal, in particular a steel material, preferably a stainless steel material, the valve seat preferably being made of a harder material than the valve body.

[0033] If the valve seat is made of a harder material than the valve disc, it can be ensured that in the event of possible plastic deformation when the valve disc is pressed or pushed onto the valve seat, the valve disc will be plastically deformed, which can be easily replaced. In this way, the counterpart valve seat, which may be a valve seat provided in a complex valve unit such as a gas handling unit, can be protected against plastic deformation.

[0034] Furthermore, it would be advantageous if at least one fluid channel, and preferably at least two fluid channels, could be led to a common sensor chamber in which a gas sensor for detecting gas is located, so that a common sensor and corresponding leak detection device can be used to monitor both seals.

[0035] Alternatively, the two fluid channels could be routed to separate sensor chambers, potentially allowing any escaping gas to be detected independently of each other.

[0036] The device according to the invention for connecting a gas-conducting conduit element to its counterpart can therefore be realized in a very simple and cost-effective manner, advantageously facilitating documentation and certification. It is therefore particularly suitable for sealing in systems in which hydrogen, in particular compressed hydrogen, or compressed natural gas is used. Such systems, which are subject to particularly high temperature fluctuations, tension fluctuations, and vibrations, are found in particular in vehicles in which hydrogen at pressures of up to 700 bar or natural gas, typically at 260 bar, is used as fuel to drive the vehicle, for example via a fuel cell.

[0037] In the context of the present invention, the term "vehicle" or "means of transportation" or other similar terms includes motor vehicles in general, such as sports utility vehicles (SUVs), buses, lorries, various commercial vehicles, water vehicles including various boats and ships, aircraft, aerial drones, etc., passenger cars including hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen vehicles, and other alternative vehicles. As used herein, a hybrid vehicle is a vehicle with more than one energy source, for example, a vehicle that is both gasoline-powered and electrically powered.

[0038] The present invention also relates to a method for connecting a gas conducting conduit element, in particular a hydrogen conducting conduit element, to a counterpart, in particular a component, preferably using the above-mentioned device, which method comprises the steps of inserting a threaded body into a complementary formed recess of the counterpart and screwing the threaded body tightly into the counterpart by means of a threaded connection, in particular by pressing the valve body of the first seal against a valve seat provided in the counterpart, in particular in the recess, so that the first seal is sealed, and a second seal, operating on the principle of sealing effect, in which the sealing effect is exerted regardless of axial displacement, in particular in the installation direction, which is necessary to create the sealing effect of the first seal, is sealed, in particular between the threaded body and the recess.

[0039] Preferably, the method also includes a leak detection step, wherein an open end of a fluid channel is disposed between the first seal and the second seal, and the other end of the fluid channel opens into a sensor chamber in which a gas sensor is disposed, and wherein if there is a leak in the first seal, leaking gas flowing out or leaking from the first conduit element flows into the fluid channel and through it into the sensor chamber, and the gas sensor detects the gas, particularly hydrogen, flowing into the sensor chamber, thus detecting and signaling a leak in the first seal.

[0040] In this respect, "signal" should be understood to mean that the gas sensor sends a signal to a control, in particular a vehicle control, to communicate the fact that leaking gas has been detected and that there is therefore a leak in the monitored seal or threaded connection. This is then communicated, for example via this control, to a display, which then lights up or shows a corresponding warning signal.

[0041] As already indicated above, the device for connecting a gas conducting conduit element, in particular a hydrogen conducting conduit element, to a counterpart, in particular a component, can be used in the described method for connecting a gas conducting conduit element to a counterpart. The further features disclosed in connection with the above description of this device can therefore also be applied to this method. The same applies to this method in reverse.

[0042] Further features and advantages of the device, use and / or method are set forth in the following description of embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0043] [Figure 1] 1 shows a schematic diagram of a known device for connecting a gas conducting conduit element to a counterpart; [Figure 2] 1 is a simplified view of an embodiment of a device according to the invention for connecting a gas conducting conduit element to a counterpart; DETAILED DESCRIPTION OF THE INVENTION

[0044] The use of the same reference numbers in different figures indicates identical, corresponding, or functionally similar elements.

[0045] FIG. 1 schematically illustrates a known device 200 for connecting a gas conducting conduit element 201 to a counterpart (not shown). The connection device illustrated in FIG. 1 is a ferrule-type connection device. As shown, such connection device 200 includes a threaded connection nut 202, a threaded coupling 203, and one or more ferrules 204, 205 mounted inside the connection nut 202. The coupling 203 typically has a contact surface 206 that engages or can be brought into engagement with a contact surface on the ferrule. A cylindrical conduit, such as a pipe end of the gas conducting conduit element 201, is inserted into the coupling 203, with the ferrules 204, 205 tightly or closely surrounding the outer wall of the conduit end. When the connection nut 202 is placed on the threaded end of the connection body, an axial force is applied to the ferrules 204, 205, causing the contact surfaces of each of the ferrules and the connection body to engage in a compressive effect, resulting in radial displacement of portions of the ferrules 204, 205, which tightly hold the outer wall of the conduit end 201. In many applications, the adapter can be assembled using a simple tool, such as a wrench.

[0046] 2 shows a simplified embodiment of an apparatus 100 according to the invention for connecting a gas-conducting conduit element 1 to a counterpart 2, the embodiment shown being part of a valve block, such as a gas handling unit. As can be seen from FIG. 2, the apparatus 100 shown consists of a cylindrical threaded body 10 extending longitudinally along the installation direction E. In the embodiment shown, the conduit element 1 to be connected is welded onto the end face of the threaded body 10 facing the counterpart 2, with the weld seam 9 being slightly oversized to ensure gas-tightness, as shown.

[0047] Furthermore, the threaded body 10 comprises, on its end face facing the counterpart 2, a flange projection 10c, which projection is provided with four through holes spaced radially in the circumferential direction, in particular spaced at an angle of 90° to one another. As can be seen from Figure 2, the counterpart 2 comprises four complementarily arranged threaded holes, by means of which the threaded body 10 can be screwed and fixed to the counterpart 2 by means of four clamping screws.

[0048] A valve body 3a, which forms a part or region of the threaded body 10, is formed on the other end face of the threaded body 10, i.e., the end face facing the counterpart 2. In the embodiment shown here, the valve body 3a is formed to have a conical shape.

[0049] The counterbore 2 is formed with a recess 2a, which has a shape, particularly a cylindrical shape, complementary to the cylindrical shape of the threaded body 10, and forms a clearance fit with said threaded body 10 when the threaded body 10 is introduced or inserted. The valve seat 4 is formed at the bottom or inner end of the recess 2a, which has a conical shape complementary to the valve body 3a. The exact contours, angles, etc. of the two elements 3a, 4 depend on the application in question, in particular the operating pressure involved, the materials of the two elements, etc. The valve body 3a can also be formed to be arched or spherical. The important thing is that an annular contact surface is formed between the two elements.

[0050] As can be seen from FIG. 2, the threaded body 10 includes two annular circumferential grooves provided on the cylindrical peripheral surface 10a, into which second and third seals 5, 8, in particular O-rings as elastic seals, are inserted and which abut airtightly against the cylindrical inner wall of the recess 2a of the counterpart 2.

[0051] When the threaded body 10 is inserted into the recess 2a and secured to the valve seat 2 by the clamping screw, the valve body 3a is pressed against the valve seat 4, forming an airtight connection or seal (first seal) between the valve body 3a and the valve seat 4, also known as a metal seal. Two additional seals (so-called safety seals) are provided by the second and third seals, which are only used if the first seal 3 develops a leak. In other words, the second and third seals 5, 8 only need to provide a sealing function if the first seal 3 begins to leak. Therefore, the second and third seals 5, 8 are positioned behind the first seal 3 in the outflow direction A of the gas leaking through the first seal 3. In other words, the second and third seals 5, 8 are positioned axially spaced from the first seal 3 in the direction opposite the installation direction E.

[0052] 2 further shows two fluid channels 7a, 7b, each having an open end. The open end of the first fluid channel 7a is disposed between the first seal 3 and the second seal 5, and the open end of the second fluid channel 7b is disposed between the second and third seals 5, 8. These two open ends of the fluid channels 7a, 7b each abut the inner surface of the recess 2a of the counterpart 2. The two fluid channels 7a, 7b can be connected to separate sensor chambers 11, each of which has a gas sensor 12 disposed therein (not shown). In this way, it is possible to determine whether only the first seal 3 (fluid channel 7a) is leaking or whether both the first seal 3 and the second seal 5 (fluid channel 7b) are leaking, independently of the other. However, in the illustrated embodiment, both fluid channels 7a, 7b are fed into a common sensor chamber 11, so that only one gas sensor is required to detect leaks in both seals 3, 5. This constitutes an advantageous variant.

[0053] Finally, Figure 2 also shows that the threaded body 10 can optionally be provided with a fluid channel 7c, in which case the open end of the fluid channel 7c is located between the second and third seals 5, 8, so that a leak can only be detected if both seals (first seal 3 and second seal 5) are leaking (if two fluid channels 7a, 7b are not provided).

[0054] Those skilled in the art will appreciate that individual features described in different embodiments can also be implemented in a single embodiment, provided there are no structural incompatibilities. Similarly, different features that are described in the context of a single embodiment can also be provided in multiple embodiments individually or in any suitable subcombination. [Explanation of symbols]

[0055] 100 Device (Threaded Connection) 1 conduit element 2 Counterparts 2a Recess in counterpart 3 First Seal 3a Valve body 4 Valve seat 5 Second Seal 7a, 7b, 7c Fluidic channels (sniffer channels) 8. The Third Seal 9 Welded Connections 10 Threaded body 10a Circumferential surface 10b Through hole 10c Flange protrusion 11 Sensor Chamber 12 Gas Sensor A. Direction of leaked gas E Installation direction

Claims

1. A device (100) for connecting a gas conducting conduit element (1) to its counterpart (2), comprising: at least one threaded body (10) configured to engage with said counterpart (2); a first seal (3) in the form of a valve body (3a) adapted to come into contact with a valve seat (4) provided on said counterpart (2) or in the form of a flat seal; a second seal (5) that operates on the principle of sealing effect, whereby the sealing effect is exerted regardless of the axial displacement required to produce the sealing effect of the first seal (3); at least one fluid channel (7a, 7b, 7c) having an open end provided between the first seal (3) and the second seal (5) and configured to detect gas leaking from the gas conducting conduit element (1) and leaking through the first seal (3); Including, The device (100) is configured to perform a purely translational movement during the creation of an airtight connection between the threaded body (10) and the counterpart (2), and the threaded body (10) is provided with at least two through holes (10b) for receiving fixing screws, the through holes (10b) being arranged behind the first seal (3) and the second seal (5) in the outflow direction (A) of gas exiting the gas conducting conduit element (1) and leaking through the first seal (3).

2. 2. The device (100) according to claim 1, wherein the first seal (3) is formed as a metal seal or a curved seal, and / or the second seal (5) is formed as a radial seal, an elastic seal, an O-ring, a delta ring or a liquid seal, and / or the second seal (5) is arranged after the first seal (3) in the outflow direction (A) of gas exiting the gas conducting conduit element (1) and leaking through the first seal (3).

3. 3. The device (100) according to claim 1 or 2, wherein the valve body (3a) has at least partially a conical, round, spherical or spherical shape and / or the valve seat (4) provided on the counterpart (2) has a tapered shape.

4. The device (100) according to any one of claims 1 to 3, wherein the first seal (3) is formed on an end face of the threaded body (10) and / or the second seal (5) is provided or formed on a circumferential surface (10a) of the threaded body (10).

5. 5. The device (100) according to claim 1, wherein the valve body (3 a) and the valve seat (4) are formed so as to form an annular contact surface, the central axis of the valve seat (4) and the central axis of the valve body (3 a) are arranged parallel to each other, and the valve body (3 a) is displaceable parallel to the two central axes.

6. 2. The device (100) according to claim 1, wherein at least one fluid channel (7a, 7b, 7c) is formed in the threaded body (10) and / or the counterpart (2).

7. 7. The device (100) according to any one of claims 1 to 6, further comprising a third seal (8) formed as a radial seal, an elastic seal, an O-ring, a delta ring or a liquid seal, the third seal (8) being arranged after the first seal (3) or after the second seal (5) in the outflow direction of gas exiting the gas conducting conduit element (1) and leaking through the first seal (3).

8. 8. The device (100) of claim 7, further comprising a second fluid channel (7b) having an open end, the open end being provided between the second seal (5) and the third seal (8) and configured to detect gas leaking out of the gas conducting conduit element (1) and leaking through the first seal (3) and through the second seal (5).

9. 9. The device (100) according to any one of claims 1 to 8, wherein the gas conducting conduit element (1) is gas-tightly connected to the threaded body (10) by means of a welded connection (9).

10. 10. The device (100) according to claim 1, wherein in a sealed state the valve body (3a) of the first seal (3) is pressed against the valve seat (4) formed in the counterpart (2) via a threaded connection.

11. 11. The device (100) according to any one of claims 1 to 10, wherein the valve body (3a) and / or the valve seat (4) are made of metal.

12. 12. The device (100) according to any one of claims 1 to 11, wherein at least one of the fluid channels (7a) leads to a common sensor chamber (11) in which a gas sensor (12) for detecting a gas is arranged.

13. A method for connecting a gas conducting conduit element (1) to a counterpart (2) using a device according to any one of claims 1 to 12, comprising: Inserting a threaded body (10) into a complementary recess (2a) of said counterpart (2); screwing said threaded body (10) tightly into said counterpart (2) by means of a threaded connection; Including, The first seal (3) is sealed, A method in which a second seal (5) is brought into a sealing state, which operates on the principle of sealing effect, whereby the sealing effect is exerted regardless of the axial displacement required to produce the sealing effect of the first seal (3).

14. The method further includes a leak detection step, wherein an open end of a fluid channel (7a) is disposed between the first seal (3) and the second seal (5), and the other end of the fluid channel (7a) opens into a sensor chamber (11) in which a gas sensor (12) is disposed; if there is a leak in the first seal (3), the leaking gas exiting or escaping from the gas conducting conduit element (1) will flow into and through the fluid channel (7a) into the sensor chamber (11); 14. The method of claim 13, wherein the gas sensor (12) detects gas entering the sensor chamber (11) and thus detects a leak at the first seal (3).

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